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Stress Testing Methods in Body Structures | SINCE theoretical and empirical engineering formulas do not always apply to automobile body structure, reliance must be put on structural testing to supplement available information. In this paper the author presents a technique for complete car structural and road testing in conjunction with body tests for such purposes as: 1. Aiding development of experimental body designs. 2. Assisting in the standardization of quality control methods. 3. Solving special problems in fabrication. 4. Furthering the improvement of body-frame unit structural efficiency. 5. Investigating the use of new materials. 6. Determining safety factor of body. The search for adequate methods of determining the safety factor led to the development of the roll-over test. It is accomplished by towing a car so that the wheels on one side go up a ramp at a 15-deg angle, and at a speed of 50 mph. The car is rolled in such a manner that the windshield header receives the greatest impact. |
INSTRUMENTATION OF VIBRATION IN AN AUTOMOBILE BODY | A short movie will be shown indicating the cars being tested for shake on the road and in the laboratory, and some of the equipment will be seen in operation. Next, eight slides will be shown and a detailed description will be made of each slide. The major context will be to show: 1. The functional arrangement of the equipment. 2. The method of interpreting the data for a single point under shake conditions. 3. The method of obtaining curves for multiple point studies. 4. The solution for a general problem. |
TRENDS IN MODERN AIRCRAFT STRUCTURAL DESIGN | Although the Electra structure is based on past good practice, its higher performance and use of prop-jet engines have injected certain new situations of interest to structural engineers. Such items include the new CAA gust criteria, loads created by prop-jet engine failure, development of the “No-Hazard” windshield, engine nacelle design loads, wing loads when taxiing with full wing fuel, fail safe and fatigue, the use of large die forgings, and the bleed air duct system used for de-icing. |
PRINCIPLES OF NOISE REDUCTION | THIS paper explains a few of the basic principles of the character of sound and the mechanism of human hearing. The author describes some simple experiments which demonstrate the relationship between intensity and loudness and the nature of harmony. He also points out the difficulties of accurately analyzing sound electronically, and the resulting importance of combining the finest electronic equipment with sharp, attentive human faculties. Five basic ways to reduce noise and the mechanics of each are described. The effect of these methods on the work of the sound engineer is indicated. |
Acoustic Design and Performance of Turbojet Test Facilities | THE high noise level associated with turbojet testing creates two noise problems: 1. The reduction of noise in the neighborhood of the installation to an acceptable level. 2. The protection of operating personnel from excessive noise. Desirable sound levels are established and, on the basis of these levels, specifications are written for the acoustic treatment of the turbojet facilities. The acoustic treatment must not only be satisfactory from the point of view of noise reduction, but it must also be able to withstand the very rigorous operating conditions. High-temperature and high-velocity flow of gases through the exhaust stack makes for these rigorous conditions. Designs which meet these specifications are discussed in this paper, together with performance data obtained on these designs. |
Human Problems in Jet Air Transportation | THE human problem with jet aircraft begins even before take-off, the author points out, with discomfort and loss of efficiency from noise, and ground injuries on the field or in repair shops. In the air, although noise and vibration in the jet plane are less than with the reciprocating engine, human tolerance is matched against other extreme forces of acceleration, direction changes, temperature and pressure variations. Through detailed examination of what happens to passengers and crew in the many situations that can arise to challenge human limitations, the author shows why he believes there is need for closer cooperation between the biologist and the engineer, and for better education of crewmen in the effective use of their equipment and in their own physical limitations. |
SOUND and FUROR THE JET NOISE SUPPRESSION AGE | BEFORE an evaluation of suppressors can be made or before a sensible discussion of suppression goals can be carried on, terms, conditions, and possibilities must be understood. A five-number system for evaluating suppressors is proposed. Methods of jet noise suppression undergoing general development today include frequency shifting, jet spreading, and jet velocity reduction. Basic types of jet spreaders and velocity reducers are shown and ratings given. Combinations of types have resulted in increased suppression in many instances. |
Automobile Body Loads | SINCE passenger-car bodies cannot practically be designed to meet the abnormal stresses of collision, normally needed rigidity is a major design criterion for the modern body. Bodies must be stiff enough, the author points out, not to respond easily to the excitation caused by vibration of the unsprung mass of wheels and suspensions, but not too stiff to ride comfortably. Recent trends toward more glass area and lower body height have increased the importance of determining body loads and structural requirements. Discussed here are some of the ways in which these factors are investigated, and the results which have been achieved. |
LIGHTING THE MOTORBUS | General considerations that affect the attainment of adequate lighting are mentioned, it being stated that proper lighting of the interior of a motorbus is influenced by limitations peculiar to the service, such as vibration, scant headroom, a restricted energy supply and relatively large voltage-variations. Available types of bus-lighting equipment are analyzed as to their suitability, from six different standpoints that are stated. “Glare” is defined and means of obviating it are suggested, inclusive of a discussion of desirable types of finish for the interior with regard to reflecting surfaces. The severe vibration produced by many motorbuses demands head-lamps of more rugged construction than that used for the headlighting of private cars. Eight essentials for motorbus head-lamps are specified. A very large percentage of the glare and poor illumination of the motor vehicles on the roads results from improper adjustment or the lack of any means for adjustment of the head-lamps. Tail-lamps, stop and direction signals, step-lamps, trouble-lamps, lights for the signs and marker-lights are discussed. Standard incandescent lamps are recommended for use. The most suitable type of electrical system for motorbus service is outlined briefly, consideration being given to the wiring needed to minimize voltage-drop, switches, lamp sockets, fuses, generator and voltage regulator. |
The Satellite Airport System and the Community | This paper presents an answer to the ground barrier problem. Studies have defined problems in the following areas: maximum terminal capacity, internal roadway systems, automobile parking, freeways and access roads, airfreight, and noise. To find solutions to the above problems, a satellite system of airports has been developed which will smooth out the interfaces with all other forms of transportation for people and commodities, and will disperse the volumes entering the system. In our satellite airport system studies, the Metroport, with short elevated runways capable of handling the new vertical and short take-off aircraft, has evolved. An elevated rail, and in some cases a subway system, travelling clear of ground congestion will be a vital link in the transportation network. The Los Angeles satellite airport concept is one of the best answers to bringing air transportation to all sections of the metropolitan areas. |
Canada's Role in the Second Decade of the Space Age — Inner Space Supersonics | This paper, presented to all types of Canadian engineers, has as its objective the stimulation of their interest in the many problems yet unsolved in the aviation industry. The paper describes briefly the SST programs - the British/French “Concorde,” theUnitedStates “Boeing2707” andtheU.S.S.R. “TU-144.” Then various engineering problems such as sonic boom, sideline noise during takeoff, cosmic rays, fuel consumption, reliability, and airport requirements, are considered. Finally, ways to reduce ground time are examined. |
Passenger Car Ventilation by Design | Favorable ventilating systems in passenger cars and their influence on the rate of air flow in the passenger compartment are shown. One example shows the pressure distribution along the centerline of the body and the differences in the pressure between possible body air inlets and outlets which determine the rate of air flow with any particular ventilation system. Several ventilating methods are shown which satisfy the requirements of increased air flow, reduced noise level and defined air flow in passenger compartment, prevention of water entry, and elimination of drafts. In view of the increasing desire for a reduction of noise level inside the passenger compartment, the noise created by the wind when the windows are opened or when the doors and windows are insufficiently sealed should be eliminated by specific ventilation openings. |
Preliminary Studies of a Supersonic Business Jet | This paper discusses two possible designs, an unswept trapezoidal wing model and an essentially delta wing model for a 10 passenger Mach 2.2 Supersonic Business Jet. The studies are quite preliminary in nature and the result of team efforts in two different Senior Aerospace Vehicle Design courses at the Georgia Institute of Technology. The philosophy of the course and the selection of this particular aircraft as a project design are touched upon briefly. The body of the paper compares the two designs, and discusses in an elementary manner their aerodynamic performance, engines, and propulsion systems; some of the design details; cost; and probable noise level, including the sonic boom problem. They are not considered solution aircraft, but the designs are believed to be fairly representative of what the resulting aircraft would resemble. The work is continuing through re-cycling and optimization of the performance by computer techniques. |
Effects of The Super Sixty Series DC-8 on Airport Requirements | A welcome relief to airport runway, taxiway, gate position saturation, and air traffic congestion is offered by the new Super Sixty Series DC-8, which now carries twice as many passengers per flight. Airplane operators benefit from substantially lower direct operating costs per seat-mile and more efficient utilization of pilot manpower in an area of growing shortage. These airplanes have a special family of problems in common with earlier jets, including community annoyance caused by noise, runway strength limitations, and the requirement for an increase in terminal people and bag gage handling equipment. |
Design, Manufacture and Marketing of Cabs for Industrial and Agricultural Equipment | This paper reviews what has happened in the cab industry since earliest developments and defines the “state-of-the-art” at the present time, pointing out areas of design, engineering, and marketing that should be investigated. Some of the new developments in cab design such as pressurization for dust elimination, air conditioning, and noise abatement are discussed. |
Automatic Light Aircraft Readiness Monitor | A study has been made of the feasibility of performing maintenance inspections on Army aircraft using automatic electrical methods. Sensing devices discussed are for vibration, temperature, pressure, liquid levels, interlocks, chip detectors, and engine speed. Evaluation of tests show that much work needs to be accomplished before electrical inspection is practically feasable. |
Evaluation of Automobile Body Design | The automobile body is a total environment. An evaluation of this environment should include consideration of: seats, vision, noise level, heating system, ease of entry, ease of maintenance, instrumentation, trunk space, exterior, and styling. These points and others are reported in an annual survey made by Popular Mechanics magazine. The owners' report is sent to drivers all over the country who evaluate their new cars on the basis of likes and dislikes. The tabulated results can be a guide of the engineer and stylist alike. |
Delivering the Mail with Diesels - The Post Office Department Looks at Diesel Engines | To determine to what extent diesel power should be introduced into the 60,000 truck postal fleet, a comprehensive evaluation-type study was undertaken by the Automotive Division of the Post Office Department. The study encompassed the complete range of truck sizes from the large 65,000 gcw tractor-trucks to the small 1/4-ton three wheel scooters. Considered in the evaluation were such factors as reliability, noise level, driver reaction and vehicle performance characteristics, in addition to the usual comparison of fuel consumption. Although the complete life cycle of the representative gasoline and diesel vehicles being studied is not complete, certain interim findings concerning vehicle performance and driver acceptance do support the trend to more general use of diesel powered vehicles. |
Sonic Boom Problems And Noise from High Performance Propulsion Systems | The development of aircraft noise consciousness in its relation to the environments of persons in the airplane and on the ground is discussed. Measures to control aircraft noise in both connections are presented. The significance of environmental noise in the development of the supersonic commercial transport is considered. |
Recommended Practices for Use in the Measurement and Evaluation of Aircraft Neighborhood Noise Levels | SAE Committee A-21, Aircraft Exterior Noise Measurements, was formed in 1961 to develop recommended practices for use in the evaluation of aircraft noise as it relates to airport neighborhood annoyance problems. The general areas of interest to the committee include the measurement, propagation, prediction and subjective rating of aircraft noise. This paper discusses the evaluation of aircraft neighborhood noise levels and describes the subjective measures by which comparisons can be made. Included in the discussion are the recommended practices adopted by SAE and those that are being studied by Committee A-21. |
RESILIENT MOUNTINGS for Passenger-Car Powerplants | THIS paper discusses the application of resilient mountings to passenger-car powerplants. Resilient mountings have a threefold purpose: 1. They isolate engine vibration and torque impulses from the rest of the vehicle. 2. They insulate the engine mass from incoming excitations due to road irregularities. 3. Nos. 1 and 2 must be accomplished without allowing the powerplant mass to get into synchronous vibration with any component of the vehicle. |
Conditions of the Perfect Windshield * | This paper deals with the question of how windshields must be constructed and installed in order to provide the highest degree of protection for passengers in a crash. Material characteristics and mounting methods of laminated safety glass are discussed from the viewpoint of actual conditions (internal automobile dimensions and possible head-to-glass impact velocity) and concrete performance data are given. A test specification is also proposed. |
Manned Spacecraft Structure Versus Unmanned Spacecraft Structure | The large difference between the total numbers of manned and unmanned spacecraft and their respective missions is discussed. The environmental and functional requirements having different effects on the two spacecraft types are described. The materials characteristics involved in those requirements and the resulting typical configurations are reviewed. It is concluded that vibration and pressurized gas containment have the outstanding influence on spacecraft structural systems. It is noted that new structural factors of safety have not been derived on the basis of any rational consideration of the design conditions for stability or pressure critical structure. |
Moisture Protection of Window Lift Motors | This is an evaluation and description of the methods and materials used to moisture proof window lift motors as applied inside automotive doors. An environmental test cabinet is described. The materials and methods were tested for their ability to seal, their resistance to abuse, their application to the motor housing, their resistance to lubrication, and their cost. The methods of moisture protection investigated were: drain holes, moisture proofing materials, and positioning. Considering all aspects, gasket seals between the motor frame and the housing proved to be a superior way to protect motors from water damage. |
United States Supersonic Transport Development Program - Sonic Boom and Noise Research | Performance objectives for the United States supersonic transport airplane provide for minimum sonic boom levels, and engine noise levels no greater than generated by current large subsonic jet aircraft. A national program of sonic boom research has been pursued by the NASA, DOD, and FAA. A National Academy of Sciences committee is now providing guidance and counsel for this effort. Major recent sonic boom flight research programs, which have yielded extensive data, were the study of public reaction to sonic boom in the Oklahoma City area last year and the structural response program recently concluded at the White Sands Missile Range, New Mexico. Findings in these two sonic boom programs are presented. Engine noise, which has received attention since the inception of supersonic transport research and under design contracts, may be less for the SST than for current large subsonic jets under most conditions. A discussion of this subject is presented. |
Road Noise Control for a Car with a Tray Construction on Chassis | This paper describes experiments to find the source of the road noise in automobiles and methods for correcting it. To find the major source of road noise, the time lag of the sound waves was measured. Characteristics of a tray frame construction car were found by comparing the vibration modes of its frame with those of body-frame and unit construction cars. As a result of experiments, it was found that the tray frame construction car combines desirable features of both body-frame and unit construction cars. |
AUTOMOBILE FINISHING-VARNISH | Annual Meeting and Detroit Section Paper - As the success or failure of the finish of an automobile depends largely on the finishing-varnish, a plea is made for more scientific analyses of the problems of automobile finishing and more care in selecting and applying a suitable varnish. The qualities to be desired in a finishing-varnish are divided into two classes: the shop qualities and the service qualities. The shop qualities include color, body or viscosity, working, flowing, setting, hardening, fullness and the safety of working. The service qualities, or those that enable the varnish to withstand the various conditions of use, include resistance to break-down under the chemical action of the actinic rays of sunlight, to the destructive action of moisture and the alkalis in mud and soap, to expansion and contraction, to vibration and to abrasion. The three most important factors in estimating the service-giving qualities of varnish are said to be elasticity, moisture-resistance and the film factor. Each of the various terms mentioned is carefully defined, analyzed and explained. Among the constants that must be determined, either for checking uniformity or for use as bases of tests, are the non-volatile content, which is the starting-point in the test for elasticity and in computing the film factor, or thickness of the dried film; the ash, the flash-point and the acid number. An empirical formula is derived by which the thickness of the dried film can be estimated with accuracy; and in a series of appendices the details are given concerning tests for the drying, the safety of working, non-volatile content, ash, flash-point and acid number; the Kauri reduction test; and tests for moisture and alkali resistance. |
SPRING-MOVEMENT AND VIBRATION STUDY OF CARS IN ACTION | Previous efforts to obtain comfortable riding-qualities for passenger-carrying automobiles are mentioned, and a device that combines a recording seismograph and a spring-action recorder is illustrated and described, since such a device is essential in conducting investigations of this character. Methods governing the use of the device when studying spring action and chassis vibration are outlined, and the results obtained are presented graphically and discussed. Several unique features characterize these tests and are worthy of consideration, not only because of the results obtained thereby but as being good illustrations of what can be accomplished by substituting unusual and perhaps spectacular methods in special instances for ordinary practice that has failed to produce some desired result. |
The Chassisless or Unit-Car Question | THE experience gained over a period of many years in the development of light-weight, high-strength structures is now finding its way into the bus industry. Investigation of present-day bus operations showed the need for a road vehicle that would carry the greatest possible payload of passengers with a smaller horsepower engine without dragging along a load of dead weight and useless structure that would eat up gasoline instead of miles. A motor coach is now available in which are incorporated aircraft materials, design, and construction features resulting in a vehicle that is approximately 1000 lb. lighter than the lightest conventional design with the same engine horsepower and seating accommodations. Motor-bus operators today can reduce costs by the use of light-weight equipment provided there is no sacrifice of strength and reliability. They must also meet the ever-increasing demands of the public for quietness, comfort, absence of vibration and engine odors - all of which can be accomplished by placing the engine in the rear which automatically gives a better distribution of weight than has heretofore been possible with the front-engine design. |
Cab-Over-Engine Trucks - Their Status and Advance in Design | DEPENDING upon the location of the front wheel, the door and step are placed either at the front or back of the cab. Some designs incorporate a protruding “hood” portion, whereas others extend the cab fully forward. The engine compartment is either immediately back of the radiator or under the cross seat. The floor and seat heights are relatively higher than in the conventional truck, and better visibility is obtained. The engine hood is well insulated for heat and sometimes for sound as well. Most powerplants are removable readily for major repairs although, in most instances, major maintenance operations can be done readily within the cab. Front axle treads have been increased in order to give greater stability on the road as well as to avoid an excessively large wheelhouse. The change in weight distribution has called for considerably more study on braking distribution. The shortened wheelbase requires a more accurate location of the fifth wheel in tractor-semi-trailer service; has emphasized the importance of the steering-angle conditions of the front axle; and has brought riding qualities to the fore. Specifications and dimensional data accompany the paper, as well as drawings of typical layouts showing the cab, engine, and front-axle relationships. |
AUTOMOBILE BODY DESIGN | The author first considers the style and arrangement of the seats, the position of the rear axle as affecting the rear kick-up in the chassis frame, and the position of the rear wheels as determining the distance from the back of the front seat to a point where the curve of the rear fender cuts across the top edge of the chassis frame. The location of the driver's seat and of the steering-wheel are next considered, the discussion then passing to the requirements that affect the height of the body, the width of the rear seat, and the general shape. The evolution of the windshield is reviewed and present practice stated. Structural changes are then considered in relation to the artistic requirements, as regards the various effects obtained by varying the size or location of such details as windows, doors, moldings, panels, pillars, belt lines, etc., and the general lines necessary to produce an effect in keeping with the character of the car. The design of the wings or fenders, the weight, producing effects of light construction, and the use of aluminum are also considered, the conclusion reached being that the design of the highest type of automobile body should always be based primarily upon a high degree of practicability. |
Automobile Engineering Progress | GENERAL DESIGN and detail mechanical developments that have been made in the last year and incorporated in automobile, truck and motorcoach models for 1932 are reviewed by the author, who also points out noticeable trends in a number of directions. He deals in order with the cars as a whole and with each major component, from the powerplant to the tires and body, as found in many leading makes. Decision of the industry not to announce the details of new models until the end of the year, at or immediately before the opening of the New York Automobile Show in January, interfered with the presentation at this time of a complete picture of all the improvements made in American motor-vehicles, but enough information is believed to be given to show the more important developments and the ways in which the automotive engineers have responded to the desire of the times for greater refinement and efficiency in automobiles. The improvements are reflected in better appearance; greater comfort; reduction of air resistance, noise and weight; insulation against heat from the engine; easier control; improved visibility; longer service life of some parts; avoidance of vapor lock; enhanced safety; increased operating economy; and simplified servicing in some cases. |
The Aircraft Trend in Body Design from the Aircraft Viewpoint | AIRCRAFT have taken more from automobile design than they have given, but they can now repay much of the obligation without necessarily transgressing the requirements of production economy and reasonable design stability. Some of these possibilities are: (1) Improved streamlining of necessary exposed parts, particularly underneath, and incorporation of other accessories in the general body lines. (2) Use of curved glass in the windshield and lightening of all window material. (3) Reduction of the frame to the status of an assembly unit, with structural significance only in combination with the body. (4) More effective distribution of flange material around the doors. (5) Lightening of skin by use of internal stiffeners, particularly on top. (6) Development of a smaller, more efficient radiator and lightening of various engine parts. Most important is the mental attitude behind the work. Phenomenal production economy has been attained because almost every man in the industry has concentrated on it. Worthwhile weight and drag reduction would result if even one competent man were assigned specifically to that duty. Lightening, with streamlining, is a beneficent cycle that permits still further lightening, resulting directly in substantial operating economies and, indirectly, in lower production cost. |
New Technique for Noise Reduction | GREAT simplification of understanding and unusual results in production often follow new approaches to old problems. When noise problems are stated in terms of the familiar physical units of pressure, velocity, weight, and stiffness, basic ideas are obtained which can be applied directly to practice. In this way, most of the mysteries and the contradictions of noise problems are eliminated. In their elements, noise problems involve only simple physical factors which are understood easily, and which can be measured with available equipment. Similarly, the solutions involve the straightforward application of known and definite engineering principles. Although simple in their elements, most practical noise problems are very complex because of their combinations. Often much ingenuity is required to measure the physical characteristics of the noise which determine the human impressions obtained from it. Such determinations can be made by proper modification of the attack and the measuring equipment, and are the key to successful noise reduction. This paper gives a classification of the various means of quieting, and outlines the technique of applying them to production. The viewpoint is quite different from that usually employed, and the practicability of the method is illustrated by examples of actual jobs. |
A Designer-Manufacturer Viewpoint of Transport-Aircraft Needs | ONE of the most essential points in the development of any airplane is the necessity for complete cooperation between the operator and the contractor in regard to necessary and desirable features to be incorporated, and this is particularly important for a commercial-transport airplane. This coordination was carried through to a remarkably efficient culmination in the development of the Douglas transport for T.W.A. Points discussed include arrangement of cabin and cockpit, seating facilities, upholstery, elimination of vibration, heating and ventilating, soundproofing, toilet facilities, lighting, vision and maintenance. The care with which all these practical considerations were worked out is discussed, and special emphasis is laid on the important points of soundproofing and maintenance in which a remarkable degree of perfection has been attained. This care and attention to details is well worthwhile and only in this manner can a really successful transport be designed incorporating all the technical and practical knowledge of the operator, manufacturer and other specialists who assist in perfecting the various installations. |
Relation of Headlamp Construction to Headlamp Roadway-Performance | HEADLAMP construction is presented in summarized form, twelve needful factors being stated by the authors. Accelerated mechanical tests, which are designed to give within a few days results of what may be expected to take place after several years of road service, are conducted in the Headlight Laboratory of the University of California. These are described and illustrated under the headings: Vibration, durability, moisture, dust and electrical insulation, and the results are stated. A few correlation tests are commented upon. Headlamp vibration is treated at length, together with an analysis of headlamp vibration-characteristics, and a differentiation is made between vibration due to the engine and that due to roadway shocks. Measurement of headlight glare upon the roadway was made by obtaining continuous records of the illumination of the driver's eye from opposing cars or other equipment, the apparatus used including a photoelectric cell mounted inside the windshield in a direct line with the driver's eyes, an amplifier specially designed to cover the range of illumination and an oscillograph for obtaining a photographic record. Partial results of these tests are given. The general conclusions reached are set forth in six divisions, the last being that 0.07 ft-candle at 100 ft. is indicated as a criterion of glare. |
Practical Noise Treatment of Automobile Bodies | THE noise problem in the automobile body is complex and encompassing due to the fact that no single angle of attack is either complete or by itself sufficient to produce the desired results. Such results must be in the final analysis appreciable to the passenger's ear. For practical purposes and to meet the requirements of the industry, the problem has been divided into two parts: (a) To secure better results or greater improvements, for the same cost or less, by finding the best materials suitable in the general body-insulation practices of today. (b) To secure a complete and well-balanced job, involving a broader application of materials found to be most practical and economical, or to develop unusual products possessing unusual properties and larger capacities to function properly under given conditions. The instruments and very thorough method used are just means to an end, as in other fields of research or experimentations in which so many here have played a part. Or we may say that he who rides and hears, may also ride and see what he hears, and what we see can readily be recorded accurately. |
Design Criteria for Turbomachinery Periodic Structures to Improve Tolerance to Inflow Distortion and Resonant Oscillatory Flows | The purpose of this paper is to discuss typical problems caused by pressure waves of large amplitude propagating in a circumferential direction in turbomachinery. Opportunities for design control of cascade resonance as a means of protecting turbomachinery from these pressure waves are presented. Some of the critical areas are compressor rear frame diffuser and main combustor instability, afterburner screech, shock wave flutter instability of high-pressure ratio, variable-geometry jet nozzles, compressor stall, compressor stage 1 blade fatigue failures, and labyrinth air seal fatigue failures caused by flexural vibration of the thin walls. |
Booster Engines for Commercial Airliners | This paper discusses some of the fundamental advantages of using a special booster engine (s) for augmenting the takeoff thrust of commercial transports. The additional thrust provided by this principal offers increased route segment versatility by providing a wider range of tradeoffs in the takeoff distance, payload, range, safety, and noise level patterns for a particular aircraft. It further describes the flexibility in configurations that this principle provides the manufacturer for a given model. Also discussed in general terms is how the limited flight envelope and short operating time required for booster engines can be used to effectively reduce the engine's weight and volume. |
Ford “S” Frame | Since statistics indicate that front impact is the major accident type, Ford has been studying energy-absorbing structures for some time. Early designs such as the “ball and tube” and “rail splitter” were discarded in favor of the “S” frame. Details of the design approach and testing are given in this paper. Design objectives were increased effective collapse distance, compatibility with production practices, and maintenance of satisfactory noise, vibration, and harshness levels. Safety objectives are improved passenger compartment integrity and reduction of seat belt loads. Barrier crash tests at 30 mph (equivalent to collision into standing vehicle at 50 mph) were used to evaluate the design of the “S” frame. Results of testing indicate that occupant restraint with seat belts, combined with front end structural improvements, offer the most promise for injury reduction during service front impact accidents. |
747 ENGINE INSTALLATION FEATURES | New approaches to problems such as noise, temperature control of accessories and equipment in the nacelle, as well as improved safety features, are necessary in a modern high by-pass engine installation. The means of supporting the engine, cowling design, and maintainability features combine to improve the state of the art that a more economic airplane will result. |
Producing a Quiet and Comfortable Cab | Farm tractor cab design with respect to quiet comfort and convenience is discussed. The areas of visibility, accessibility, environmental control, and noise suppression are investigated. Various approaches to accomplish optimum conditions in these areas are analyzed, components are evaluated, and design recommendations are made. |
Methods and Problems in Noise Reduction on High Speed Diesel Engines | This paper describes a newly constructed research facility which was specifically designed for noise reduction work on internal combustion engines. Various approaches for reducing engine noise are discussed, and a method which permits locating individual sources of structure-borne sound is reviewed. A measuring system for airborne sound, radiated from the engine surfaces, is described. Some new findings and new problems encountered in noise reduction work are discussed. |
Crash Research for Vehicle Safety | The Impact Sled, a full-scale laboratory facility which simulates vehicle accidents, has been in use at the General Motors Proving Ground since late 1962. This paper describes the facility and supporting instrumentation, and reviews some of the many types of tests that were run in the first year of operation. These range from tests of complete vehicles loaded with passenger dummies to tests of single components such as seat belts, seat adjusters, door locks, and windshields. This new research tool, which produces results comparable to those of the classical barrier impact test, has proved to be a valuable and versatile addition to the automotive testing facilities at the Proving Ground. |
Aerodynamic Effects on Automotive Components | The range of automotive components that are affected by air flow around the car is surveyed, with examples of the application of aerodynamic knowledge to brake and engine cooling, wind noise, dirt accumulation, wiper lift, body ventilation, and air leakage. Air pressure distribution patterns over an automobile are shown along with air flow visualization techniques. |
Recent Developments in Penetration Resistance of Windshield Glass | A twofold improvement in penetration resistance of laminated safety glass for use in vehicle windshields has been achieved. A new test procedure has been established which will provide better correlation of test conditions to accident conditions than present tests do. Present windshield material and the new safety glazings are compared. |
Airport Compatibility with the SST - Problems of Ground Support Equipment | The compatibility of a supersonic transport with 15 international United States civil airports is examined in the principal areas of: terminals, passenger handling, and ground support equipment; runway length and pavement strength; and airport and community noise. Some new support equipment and facilities will be required although they are considered to be evolutionary in nature rather than requiring radical departures from current design. Runways and pavement strengths are generally acceptable as they exist today. Noise, both in the terminal areas and in the surrounding community, is expected to be equivalent to, or less than that of contemporary subsonic jet transport aircraft. |
Automobile Driver Eye Position | This paper reports results of a driver eye position survey made to provide the automobile industry with standardized data on driver eye location. Coordinate anthropometric measurements of eye position and top of head were recorded on film by a special photogrammetric technique. Data were smoothed into elliptical tangent cutoff percentile contours referenced to car body inch-lines and to points on the manikin. Results revealed a new shape to the driver’s eye position zone, compared to the area outlined in SAE J906, Glazing Manual. |
Efficiency in the Use of Shop Space | The growth rate of motor common carriers of general commodities has been greatest from 1950–1960. Being a service business, the increased facilities required, primarily the freight terminals and garage buildings, necessarily lagged behind the business being handled. Many factors must be considered before construction is begun. Planning necessarily includes geographical location, adequacy to handle the vehicles that will be assigned for maintenance, design of the building, and the extremely difficult matter of cost. The author’s concept of the most efficient garage building is that it be rectangular in shape, have a flat roof, parallel service bays of a standard width with corresponding power-operated overhead doors, space heaters of the self-contained type mounted overhead, storage space located on second floors, and all stationary shop equipment mounted overhead or under the floor. Most important though is the efficient use of all floor space. |
An Approach to the Isolation and Control of Vibration in Light Business Aircraft | This paper presents an approach utilized by a light business aircraft manufacturer in resolving vibrational problems. The discussion relates the principle sources of vibration; objective briefly explores the consideration of priority in the operational range of the aircraft. The approach phases--preventive measures, theoretical application, and practical application--are illustrated through an actual vibration problem solution. It is concluded that this approach has proved satisfactory and that the importance of the practical aspect cannot be underestimated. |
An Automotive Living Room on wheels | The family car of a not-too-distant tomorrow will be “an automotive living room on wheels.” An air-conditioned vehicle equipped with television for back-seat riders, pull-out tables for games or dining, vanity-table and clothes-storage compartments, seats that convert into luxuriously upholstered davenports, or serve as sleeping couches when the car's recessed window blinds are pulled down. The power plant and driving line will be simplified to one of three procedures: a front engine front drive, a rear engine rear drive, or a turbine or fuel cell all-wheel drive. The entire design will be based on the largest possible “living room” mounted between the most reasonable wheelbase and without noticeable overhang. |
A Shipbuilder's Views on River Towboat Vibration | This paper discusses causes, prevention, and possible corrective measures for river towboat vibration. Also discussed is the problem of resolving the amount of vibration acceptable to both owners and builders before corrective action is indicated in a specific vessel. The author suggests that sufficient research into towboat vibration be accomplished to establish some numerical parameters that can be used as standards of acceptance for vibration limits. |
Wind Noise - A Practical Approach | The principle cause of objectionable wind noise in the modern automobile is small air leaks in certain critical areas. The aerodynamic shape is insignificant in overall wind noise. The critical areas in order of importance are: 1. Vent window and door to “A” post sealing from the roof rail to about a foot below the beltline. 2. “C” post area at beltline. 3. Upper rear of front door area. 4. All other areas from roof rail to a foot below the beltline. Conclusions reached after extensive testing show that wind noise can be eliminated by good sealing about the doors and windows. |
Vehicle Vertical Vibration and Tire Performance | In the first part of this paper methods recently developed for the study of the oscillations of running vehicles are described as well as two types of analysis. Some information about the apparatus used for recording and analysis are given. In the second part the results of the analysis of the vertical vibration of a car fitted with three types of tires running on various types of road at various speeds are presented and discussed. Finally, in the third part, the possible influences of tires on the vertical vibration of the vehicle are surveyed. The viscoelastic deformations of the tires cause middle frequency oscillations which are transmitted from the tires to the unsprung masses and to the car body. |
THE POSTWAR CAR AND THE A-BLAST…WHAT ARE THE ODDS? | WHAT would happen if an atomic bomb were to explode at noon tomorrow without warning of any kind? Would the automobile turn out to be a death trap for many of us or would it offer as much protection as the ordinary building? Would there be any advantage in having the car turned away from the center of the blast or to having the windows rolled down? Would it be safer to crouch down on the floor of the car at the first sign of an atomic explosion? Would it be safe to enter our cars as soon as the first effects of the explosion have subsided? Would the cars run? It was to find the answers to some of these questions that a group was invited to observe an experiment at the Nevada Proving Ground of the Atomic Energy Commission. This group - which became the SAE-FCDA Advisory Committee - wrote the accompanying report, which tells about the experiment and some of the things that were learned. A. L. Haynes of Ford is chairman of the committee. Other members are: R. B. Alexander of Packard, William Christensen of Nash-Kelvinator, V. B. Corey of Willys, N. F. Hadley of Chrysler, E. J. Martin and M. V. Muzzy of GMC, W. W. Smith of Studebaker, A. D. Wagner of Hudson, and R. C. Sackett of SAE, secretary. |
A TECHNIQUE FOR DETERMINING THE OCTANE NUMBER REQUIREMENTS OF COMMERCIAL VEHICLES | Despite the size and importance of the fleet market, refiners have little information on the antiknock requirements of commercial vehicles. Considerable interest has been displayed in obtaining reliable data in this area. Some road survey data have been obtained in the past; however, truck engines are more prone to high-speed knock due to today’s more sensitive fuels and higher governed speeds. Knock under these conditions is more damaging and cannot be heard due to the masking effect of the high level of vehicle noise on the road. A chassis dynamometer technique has been developed to overcome this noise barrier and thereby provide realistic octane requirement data. Data obtained with this technique on commercial-type fuels were used to construct what is described as an “octane requirement map”. This map extends the usefulness of the data and is a unique and effective means of expressing octane requirements, particularly how requirements are related to the sensitivity of the fuel. The map is also used to describe a new concept in determining relative engine severity. |
Automobile Side-Impact Collisions, Series II | Engineering methodology and research techniques, applied to 12 intersection-type automobile collision experiments, provided data on four speeds of impact and on three positions of impact. Anthropometric dummy motorists provide collision force and kinematic data for several conditions of restraint. Advanced photographic equipment identify new approaches to solution of the motorist collision injury problem. Specific data include tri-axial acceleration patterns for motorist head and chest and for car passenger compartment; identification of many factors associated with door latch failure and motorist ejection; demonstration of protection provided by the shoulder strap and lap belt combination; preliminary findings on tempered side window glass breakage and related head impact accelerations; collision dynamics and why modern car design has reduced probability for intersection collision roll-over; car collision deformation, skid patterns, and cost to repair damages are given for these controlled exposures. Successful programming of collision transducer patterns for data reduction by 7090 computer also is described. |
SST Operations and Maintenance Considerations | The SST pilot will have at his command more automatic equipment and better readout and displays to control noise level near the airport, to program the climb for minimum sonic boom, and to operate the airplane to lower weather minimums than on any previous transport. Yet, Boeing believes the typical senior airline captain will make the transition without any difficulty. The SST mechanic will have new and larger facilities, will handle bigger and heavier equipment, will learn to maintain airplanes still hot with residual heat, and will learn to maintain and repair that new metal titanium. Yet, the mechanic will find the SST maintenance and repair the best planned and organized of any airplane program to date. |
The Body Engineer's Role in Automotive Aerodynamics | Aerodynamic streamlining is assuming greater importance with our sustained driving speeds on new expressways. Benefits of streamlining include reduced wind noise, reduced lift and better stability, improved acceleration at passing speeds, higher cruising and top speeds, better fuel economy, and reduced initial costs. Basic principles of aerodynamics for automobiles are presented. Application of these principles are discussed and depicted for different types of automobiles and a tractor-trailer unit. Tables, formulas, and examples are included. Trends show aerodynamics as a factor of increasing importance for the automobile. It is suggested that a joint training program be initiated for body engineers and aerodynamicists with classroom studies based on detail design problems. |
A New Look at the Aircraft Noise Problem | This paper presents an analysis of the airport community noise problem, based on the assumptions that some significant adjustments will be made to reduce the impact of aircraft noise on the community, and that these adjustments can be made in an atmosphere of cooperation among engine and airplane manufacturers, airline and airport operators, and communities. Such cooperation can make available combined know-how to arrive at adjustments that will cause minimum loss to all interested parties. |
Control of Double Images in Automobile Glass | This paper first examines the optical principles involved in the formation of double images so that glass may be evaluated for this property in the design stage of automobile windshields. It then describes a new instrument, the local curvature and wedge meter, which has proved to be useful in determining the extent to which each of the three factors of curvature, inclination, and wedge has contributed to the presence of double images. |
Silent Mercury Rankine Cycle Power System | A silent mercury Rankine cycle power system is under development at TRW for U. S. Army Mobility Command's Engineer Research and Development Laboratories, Fort Belvoir, Va. The 3 kwe SCAP (Silent Compact Auxiliary Power) system is a power generator unit designed for various hydrocarbon fuels. The main advantages are portability and the inaudibility at 100 ft with a low ambient noise level. The system consists of a mercury boiler, a high-speed mercury driven turboalternator pump unit, an aircooled mercury condenser, and necessary system controls. Since this system converts heat through a closed loop mercury Rankine cycle engine into useful electrical power, the design is adaptable to burning indigenous fuels. A complete 3 kw useful electrical output system burning hydrocarbon fuels will weigh 125 lb and have a fuel consumption of 6.35 lb/hr. |
Lead for Noise Control | A variety of forms of lead and leaded materials for controlling noise and vibration is available today. These forms are classified by type and use, and the theory of their performance is examined cursorily in this paper. To describe the application of these materials for acoustic purposes, five examples are given to show their effectiveness in reducing sound levels. |
Electrical Discharge Machining in Production | Republic Aviation Corp. had a manufacturing problem with drilling the speed brake door of the F-105 airplane. The door is composed of annealed and heat treated Rene 41, Inconel X and titanium. To overcome this problem, electrical discharge machining was utilized to produce required holes, resulting in significant cost savings over traditional methods. |
Injury in Non-Fatal Accidents * | The research paper presented here is the result of an investigation by a medical-engineering team. The study applies techniques of experimental automobile-collision injury analysis to human injuries resulting from accidental collisions. The accident characteristics, observed injury patterns, and human kinematics are presented and analyzed. The study emphasizes injuries sustained from windshield glass. Present glass characteristics are discussed and suggestions based on the cases presented are made regarding future glass technology. |
Aerodynamic Wind Throb in Passenger Cars | Most automobiles, at certain speeds with at least one window open, develop a pulsating pressure which is felt mainly through the ears and is objectionable to the occupants. While this “aerodynamic wind throb” is noticeable over a range of speeds, there is a fairly pronounced peak in the effect at one speed. This problem is studied analytically and experimentally. It is established that the car is a dynamic system consisting of a Helmholtz resonator excited by an edge tone. It is shown that the trouble can be corrected by changing the natural frequency, minimizing or eliminating the excitation, or increasing damping of the system. |
The WHY and HOW of THE RUBBER-TIRED RAILROAD-COACH | Railroads are facing a crisis in operating costs, the urge toward reduction of unnecessary weight has become widespread and the crusade for noise abatement is no longer to be denied, according to the author. The pneumatic-tired railroad-coach not only answers these requirements, he says, but anticipates a demand for a new traveling comfort. The desire to rubberize railroad equipment is old but much fruitless research has resulted from directing it chiefly toward solid-rubber or cushion tires. Road and rail surfaces present entirely different problems so far as the tire is concerned. No uniformity of conditions obtains on highways but rails are even and smooth. A badly aligned joint such as would wreck a metal wheel makes no impression on a pneumatic tire. As simple as the tire problem may seem, its solution represents years of courageous and skillful research on the part of the Michelin company in France. Out of this has been evolved a rail-car tire which has a life comparable with that of tires in highway service and therefore is commercially acceptable. Facts from tire-performance data are stated and it is shown that light coach weight is the major need. The Budd-Michelin rail-coach is described and also the Reading-65 rail-coach. Weight comparisons are made and rail-coach body-design is discussed, as well as cost of weight. |
The Place of Sound Measurements in Automotive-Noise Reduction | THE desirability of measuring sound by soundmeter, rather than by listening with human ears, is expressed by the author, who states that soundmeter measurements indicate definitely just what components of noises must be reduced and also just what has been accomplished by any given change. Usually, they may be taken so as to indicate the part responsible for the noise, and even the nature of the defect. He then considers some fundamental characteristics of human ears and of various sounds. The apparent inconsistencies of the mass of data obtained from soundmeter measurements made in connection with practical noise-problems are explained, and the physical problem of what soundmeters measure is presented, together with a discussion of the subject of sound pressure and the use of the decibel scale of sound measurement which includes definitions of the various terms and units employed. The psychological problem, that is, the interpretation of sound measurements in terms of ear sensations, is presented at length and followed by a summary. The practical problem, that is, the technique of noise reduction, is analyzed also, quieting methods are suggested under seven specific headings, and it is stated as a conclusion that sound measurements obtained with measuring instruments are an indispensable aid in achieving logical noise-reduction. |